7 Reasons the Terrafugia Transition Isn't Coming to Your Garage

Terrafugia's flying car, on display at the New York International Auto Show this week, is an impressive execution of the flying car concept. But there are plenty of good reasons why we won't soon have roadable planes.

Everyone loves the Terrafugia Transition, the cute-as-a-bug flying car that has been center stage at the New York International Auto Show this week. Among the media reporting enthusiastically on its car-show debut were The New York Times and the Los Angeles Times. CNN was there, too, declaring, "Flying cars are not just the stuff of sci-fi movies anymore."

You might think that PopMech would be on board with this rapturous reception. We've always been boosters of the flying car idea, and once hoped that we'd all be flying around in them by now. But we've also always tried to inject a dose of realism into our reporting and face the reality that the compromises involved in trying to do both air and land well are prohibitive.

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We salute Terrafugia for finding a workable compromise between sky and land requirements; from an engineering perspective, it's an impressive accomplishment. But the limitations remain enormous, and so we remain skeptical that a vehicle of this sort will ever become more than a novelty craft.

Here's why:

1. It will be hard to produce for the advertised price.

Aircraft almost always cost more to build than originally estimated—often, much, much more. For example: When Vern Raburn conceived the Eclipse 500 Very Light Jet, its revolutionary design was going to provide a twin-engine turbofan plane for the masses, with each selling for just $1 million. Unfortunately, before you build a lot, you have to build a couple, and that's expensive. Soon after the Eclipse finally hit the market, the price was raised to $2.15 million. Not enough were sold to make production economical. The company filed for bankruptcy later that same year.

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The Terrafugia's $279,000 price point is a lot lower. But it's still based on assumptions about labor costs, production efficiency, the price of raw materials, and more. By way of comparison, the Terrafugia's current price tag is about the same as that of a new Cessna 172, the most-produced aircraft in history. And its development costs were amortized before Terrafugia's builders were even born.

For its part, Terrafugia is standing by its projected price. "That figure is based on our production prototyping, so we are fairly confident in it," chief operating officer Anna Dietrich says. "Of course, things like energy costs affect the price of all the raw materials, so it is possible that something could drive it up."

Speaking of the Cessna 172, that plane has been fully certified by the FAA under its Part 23 rules, which means it can be used for anything you might want to use an airplane for. The Terrafugia is aiming for certification under much looser, less expensive rules called Light Sport Aircraft, or LSA. But because such planes have to meet less stringent safety requirements, the FAA puts greater restrictions on their use. These planes cannot be used commercially, for instance, and they can carry only one passenger in addition to the pilot.

There is also a strict limit on the aircraft's maximum gross weight, which could prove problematic: The reality is that most people who can afford to fly and have the time to do so are middle-aged or older, and many of these people have a hard time keeping control of their expanding waistlines. The flying club I belong to recently decided to sell its Cessna 152, a two-seat light plane with similar characteristics to the Terrafugia, because too few members were able to fly with a passenger without violating the weight limit.

3. The light aircraft market is extraordinarily tough.

A quarter-million is a lot of money for such a restricted aircraft. When Cessna considered entering the LSA market, the company decided it would be feasible only if it could sell aircraft for less than $100,000. By shifting production to China, it nearly managed to meet that goal; the resulting aircraft, the Cessna Skycatcher, was sold initially for $109,500. But even Cessna couldn't sustain such a low price point. Last year, having delivered about 100 of the aircraft, the company upped the price to $149,000.

While the market for top-end business jets is booming (Google's top three execs have eight jets among them), the lower you go down the market, the worse business is. When it comes to single-engine piston planes, you can hear crickets chirping.

4. Its legal future is cloudy.

Terrafugia's ambition is to be certified as a Light Sport Aircraft. But the company first has to complete its flight testing program, which it hopes to do by early 2013. "We have six phases of the flight testing laid out," Dietrich says. "At the completion of those tests, assuming everything goes as planned, we'll be able to declare compliance to all of the FAA's light sport standards."

We wish them well, but there's a long way to go. For its part, the FAA has released a statement that reads, in part: "The manufacturer has not yet applied for an FAA airworthiness certificate, so the FAA has not yet determined what level of pilot certificate and training would be required to operate the Terrafugia Transition as an aircraft." That's a hurdle Terrafugia will need to clear before it can make its first delivery.

Meanwhile, the Department of Transportation has deemed the Transition roadworthy—thanks to several temporary waivers. It's far from guaranteed that those waivers will be renewed.

5. Design compromises will take a serious toll on performance.

Aircraft and planes occupy very different environments, and as a result, face very different design requirements. Planes must be lightweight in order to move efficiently through the air; cars must be strong and dense to survive impacts. Planes must have long wings to push down the air; cars must be small to minimize air resistance. No vehicle capable of operating in both environments will excel at either.

In Terrafugia's defense, Dietrich points out that virtually every man-made object involves a compromise of some sort. "Every product you buy, every vehicle, every aircraft is a compromise," Dietrich says. "You trade high performance for style, or safety. You are always making design choices. You're always making tradeoffs."

Not every compromise is equally severe, however. Just by looking at the Terrafugia's design, you can tell it's going to suffer from efficiency and control issues. Because it's relatively short, the control surfaces on the tail won't have much leverage, so the plane is going to be relatively unstable along the longitudinal axis. And look at that front canard: It's right in front of the main part of the car body, which will disrupt airflow and make the plane less effective.

6. Roadability's benefits don't outweigh its penalties.

In exchange for its severe limitations in performance, what does the Transition's roadworthiness give you in return? The ability to drive away from an airport after you land. In a world where no one owned a car, this would be a game-changer. In the real world, a pickup by a friend or a rental car is just a phone call (or text) away.

7. Past precedents are not encouraging.

The idea of the flying car, or roadable plane, has been tried many times before, and has failed. One of the more promising made headlines in the '40s and '50s, when Robert Edison Fulton introduced a roadable aircraft he called the Airphibian. The vehicle was a small two-passenger car to which wings and a tail could be attached. It flew successfully, and Fulton and his team logged hundreds of thousands of miles of driving and flying. But performance was anemic, and sales never materialized.

Another riff on the same idea was the Aerocar, a vehicle dreamed up by a Washington State inventor named Moulton Taylor. The Aerocar looked a lot like the Airphibian, but its wings folded up on the ground and pulled behind the car like a trailer. This offered greater convenience, but no greater success: Taylor could never attract enough orders to start production.

Terrafugia could be in the same boat. What it has created is an admirable execution of the flying car concept, but flying cars simply are still too costly and impractical for the dream to become more than a novelty anytime soon.

Jeff Wise is a contributing editor for Popular Mechanics and the author of Extreme Fear: The Science of Your Mind in Danger. For a daily dose of extreme fear, check out his blog.